> There are obvious limitations to this, including if you want to break
> from "natural order", but hopefully this will save someone out there a
It's the assumption that breaking the natural order is common that makes
explicit tabindex values a requirement for accessibility standards. If
the natural order applies, there is no need for them, except to avoid making
that a special case. What I suspect you are doing here is providing a
solution to a legislation requirement, rather than an accessibility one;
there is some risk that people will not then think about the consequences
of unnatural orders, and you will be left in the same position as with
no tabindex values used at all.
To be useful in preparing static pages, this technique needs to leave
gaps in the number. It's no use for dynamic pages as it simply reproduces
the default behaviour.